The September 11 assault on the US has triggered tectonic changes in American foreign policy. But it has also presented the US with a unique opportunity to move Palestinian and Israeli leaders towards a renewed peace process that before the terrorist attacks had become a distant memory.
The personal histories of Ariel Sharon, Israeli prime minister, and Yassir Arafat, leader of the Palestinian Authority, always aroused understandable scepticism about the sincerity of their proclaimed commitment to a peace agreement that respected the legitimacy of their respective national claims. Nevertheless, many in Israel have argued that it is Mr Sharon's hawkishness that will enable him to win over most Israelis to support the painful compromises that even he recognises as necessary to end the conflict.
Similarly, many believe that Mr Arafat had come to understand the futility of an intifada that has yielded Palestinians no political advantages - no international intervention on behalf of the Palestinians and not even meaningful Arab support. Mr Sharon had managed to calibrate a level of counter-violence that was systematically dismembering the Palestinian economy, its infrastructure and the Palestinian Authority's institutions and leadership - while at the same time projecting a level of restraint sufficient to prevent US or international intervention.
Nevertheless, without an assurance of some tangible political gain Mr Arafat was unable to end the violence for fear that he would be seen by Palestinians as having capitulated ignominiously to Sharon. For his part, Mr Sharon could not relent on his refusal to make any political concessions to Mr Arafat for fear that it would compromise the hawkish image he needs to make the necessary concessions once the political process begins. Thus, according to this benign view of the two leaders, they were both locked into positions that paralysed the peace process.
If this reading of the two men were correct, the dramatic changes brought about by the September 11 assault on the US should have provided them with ladders to climb down from the limb they were out on. A decision by Mr Arafat at that point to end the violence would have been seen by most Palestinians not as surrender to Israel but as a necessary accommodation to a war on terrorism that would advance the Palestinian cause.
And a declaration by Mr Sharon of his willingness to link discussions of a renewed political process to discussions of a Palestinian ceasefire - something he has refused to do so far - would have been seen by most Israelis after September 11 as an act of statesmanship, not weakness. For if the war on global terror were to fail, no state would be left more exposed to terrorist fundamentalism than Israel.
But neither Mr Arafat nor Mr Sharon has risen to the occasion - at least not yet. Mr Arafat did declare a ceasefire shortly after September 11 but it was deeply flawed. At first, Palestinian violence, particularly terrorism, subsided dramatically (even according to Israeli intelligence agencies). But it quickly flared up again, in part because Mr Arafat apparently believed that the US was sufficiently in need of Arab and Muslim support to enable him to continue a low level of violence to satisfy his internal opposition. However, there have been indications these past few days that he is at last exerting the 100 per cent effort demanded by the US. Indeed, the killing of two pro-bin
Laden Palestinian demonstrators by Palestinian police suggests a less-than-welcome zealousness.
For his part, Mr Sharon at first saw the September 11 tragedy as a hunting licence to finish off the Palestinian Authority's leadership and the Palestinian dream of statehood. When Mr Sharon realised that events had in fact granted Mr Arafat a new lease of life - he was asked by the US to participate in the new coalition against terrorism that it was forming - Mr Sharon's bitterness led to intemperate criticism of President George W. Bush as a latter-day Neville Chamberlain.
Mr Sharon apologised but he continued his criticism of Mr Arafat as Israel's Osama bin Laden and a pathological liar. When it comes to telling the truth, however, Mr Sharon's actions only underscore his similarity to Mr Arafat. For despite Mr Sharon's solemn word that Israel would no longer build new settlements - a promise that was part of the guidelines of the coalition government he heads - Mr Sharon approved the construction of at least 10 new settlements in the West Bank and Gaza.
Nevertheless, the overriding priority of the war on terrorism has created a new opportunity for the US administration to renew an Israeli-Palestinian peace process. The US now has the leverage and, domestically, the political room to make certain reasonable and balanced demands of both sides.
The first is that Mr Arafat finally declare - without equivocation - the Palestinians' unqualified recognition of Israel's legitimacy on every last inch of its pre-1967 borders, even as Palestinians insist on retaining every last inch on their side of that border for a sovereign and independent state. There can no longer be any ambiguity about an alleged Palestinian policy of stages: it must be repudiated explicitly.
Second, and in response to such a clear Palestinian declaration, the US can demand of Mr Sharon that he end all settlement activity and dismantle the newest settlements established in violation of his promise. The US should also insist that he commit to prompt implementation of the Mitchell commission's recommendations and the various provisions of the Oslo accords and Wye understandings that Israel has failed to implement, including the remaining redeployments of the Israeli Defence Forces.
For now, a final status agreement between Israel and the Palestinians may be out of the reach of Mr Sharon and Mr Arafat. But the US has the leverage to demand of the parties the meticulous observance of a ceasefire, the shutting down of terrorist organisations by the Palestinians and the removal by Israel of its devastating choke-hold on Palestinian life, all of which are necessary to create the space within which the reconstruction of a Middle East peace process becomes possible.
The writer is senior fellow at the Council on Foreign Relations.